Project Summary/Abstract There are more than 2 million Americans with opioid use disorder (OUD), contributing to unprecedented levels of overdoses and drug-related mortality in the U.S. Several approved medications for OUD (MOUD) are available, and robust evidence shows them to be more effective than abstinence or psychosocial therapy alone in helping individuals achieve and maintain remission. Yet, less than 20% of individuals with OUD receive any MOUD. Buprenorphine maintenance therapy (BMT) holds significant potential to increase access to treatment as the only MOUD available in a primary care setting that does not require patients to endure withdrawal. Fewer than 7% of physicians prescribe the drug, and more than 40% of U.S. counties do not have a BMT provider, with access further restricted in rural and otherwise underserved areas. It seems that provider-, patient-, and system-level barriers are fueling an ?implementation chasm? between the evidence-based practice for OUD and its actual delivery. The objective of this application for a NIDA Mentored Research Scientist Development Award (K01) is to support a new assistant professor in the Emory University Rollins School of Public Health to become a national leader in pioneering innovative, multilevel research on how to close this implementation chasm and reduce drug-related harms and inequities in those harms. To that end, this K01 application provides training opportunities in Implementation Science, spatial analysis, qualitative methods, and addiction medicine. The research aims are designed to reinforce these new skills, using mixed methods and a conceptual model derived from Implementation Science (i.e., the Consolidated Framework for Implementation Research and the Diffusion of Innovations theoretical model) to investigate the modifiable barriers and facilitators to BMT adoption in primary care. Aim 1 uses spatial analysis to develop annual, county-level measures of OUD and BMT treatment availability and determine the local correlates of unmet treatment need, both overall and for disparity populations. Aim 2 observes the diffusion of BMT prescribing among primary care providers, measuring the significant predictors of BMT adoption, including individual-, practice-, system-, and community-level factors. Aim 3 will identify ?positive deviant? counties?i.e., those with substantial increases in BMT prescribing over time?and conduct in-depth qualitative case studies to determine the processes associated with successful BMT implementation and sustainment, including novel models of care and local adaptations of best practices. These studies will provide actionable recommendations for communities and health systems seeking to increase access to evidence-based care for OUD. The protected time, resources, and mentorship available through this K01 award will enable Dr. Yarbrough to emerge as an independent and leading researcher in substance use disorders and Implementation Science who will help close the implementation chasm for MOUD treatments and improve outcomes for opioid use disorder patients.